They cannot let him enter next season without an extension as it will kill any chance he has to recruit in the off-season.
So the time to execute the above plan you lay out was much earlier than now. Barring some miraculous upsets of a combo of BSU, USU and SDSU there is no way they can legitimately extend him.
And they can’t let him dangle without an extension without putting recruiting in absolute jeopardy and scuttling any hope of a decent roster 3-4 years down the road.